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These are the user uploaded subtitles that are being translated: 0 00:00:00,010 --> 00:00:07,777 1 00:00:06,473 --> 00:00:09,541 Neutron stars. 2 00:00:09,543 --> 00:00:11,676 Super heavy, super dense. 3 00:00:11,678 --> 00:00:13,011 Extreme. 4 00:00:13,013 --> 00:00:17,215 Gravitational, magnetic, hot. 5 00:00:17,217 --> 00:00:18,950 Scary. 6 00:00:18,952 --> 00:00:21,953 They destroy planets. 7 00:00:21,955 --> 00:00:24,656 They can even destroy stars. 8 00:00:24,658 --> 00:00:27,091 A cosmic conundrum. 9 00:00:27,093 --> 00:00:29,961 They're very, very massive, 10 00:00:29,963 --> 00:00:31,963 but they're also really, really small. 11 00:00:31,965 --> 00:00:34,298 Tiny cosmic super powers 12 00:00:34,300 --> 00:00:37,369 long overshadowed by black holes ... 13 00:00:37,371 --> 00:00:39,504 until now. 14 00:00:39,506 --> 00:00:41,706 Neutron stars have been thrust very much 15 00:00:41,708 --> 00:00:44,109 to the forefront of modern astrophysics. 16 00:00:44,111 --> 00:00:47,511 The world's astronomers know that something is happening. 17 00:00:47,513 --> 00:00:50,448 Something's up, it's new, and it's different. 18 00:00:50,450 --> 00:00:54,585 Neutron stars are the most interesting 19 00:00:54,587 --> 00:00:57,989 astrophysical object in the universe. 20 00:00:57,991 --> 00:01:00,658 Now firmly in the limelight, 21 00:01:00,660 --> 00:01:05,565 neutron stars, creators of our most precious elements 22 00:01:05,567 --> 00:01:07,399 and life itself. 23 00:01:10,470 --> 00:01:13,438 captions paid for by discovery communications 24 00:01:25,818 --> 00:01:29,553 130 million light years form earth, 25 00:01:29,555 --> 00:01:34,492 a galaxy called "ngc-4993." 26 00:01:34,494 --> 00:01:39,197 Two dead stars trapped in a rapidly diminishing spiral. 27 00:01:45,907 --> 00:01:49,240 It's like listening to the ringing of the cosmos itself. 28 00:01:49,242 --> 00:01:51,309 The sound of that collision, if you will, 29 00:01:51,311 --> 00:01:55,847 imprinted on the fabric of space and time itself. 30 00:01:55,849 --> 00:02:01,519 Livingston, Louisiana, the advanced ligo observatory. 31 00:02:01,521 --> 00:02:04,455 Its mission ... to detect gravitational waves 32 00:02:04,457 --> 00:02:06,057 generated in space. 33 00:02:08,394 --> 00:02:11,931 A gravitational wave is a distortion of space time 34 00:02:11,933 --> 00:02:13,198 that's caused by, usually, 35 00:02:13,200 --> 00:02:17,334 some kind of very traumatic gravitational event. 36 00:02:17,336 --> 00:02:20,071 Events such as a supernova, 37 00:02:20,073 --> 00:02:23,508 or the collision of black holes, or massive stars. 38 00:02:25,345 --> 00:02:30,748 2015 ... ligo makes history by detecting gravitational waves 39 00:02:30,750 --> 00:02:32,284 for the first time, 40 00:02:32,286 --> 00:02:36,687 100 years after Einstein's prediction. 41 00:02:36,689 --> 00:02:41,827 It's the signature of the crash of black holes. 42 00:02:41,829 --> 00:02:43,762 It's almost like listening to the sound 43 00:02:43,764 --> 00:02:47,031 of a distant car crash that you didn't witness. 44 00:02:47,033 --> 00:02:48,901 But you're so clever, 45 00:02:48,903 --> 00:02:52,270 and the sound of this car crash is such a unique signature, 46 00:02:52,272 --> 00:02:54,906 that you are able to use your computers to model 47 00:02:54,908 --> 00:02:59,910 exactly the type of cars that must have collided together. 48 00:02:59,912 --> 00:03:03,381 In 2017, ligo picks up a different 49 00:03:03,383 --> 00:03:05,917 kind of signal. 50 00:03:05,919 --> 00:03:08,653 The unfolding of the August 2017 event 51 00:03:08,655 --> 00:03:11,322 was nothing short of extraordinary. 52 00:03:11,324 --> 00:03:14,726 So, the signal comes in, and the signal is strange. 53 00:03:14,728 --> 00:03:17,729 It has a long-lasting signal. 54 00:03:17,731 --> 00:03:19,198 It's over 100 seconds. 55 00:03:19,200 --> 00:03:22,133 Less than two seconds later, a gamma-ray telescope 56 00:03:22,135 --> 00:03:24,736 detected a flash of gamma rays 57 00:03:24,738 --> 00:03:27,205 from that same part of the sky. 58 00:03:27,207 --> 00:03:30,274 And very quickly, the world's astronomers 59 00:03:30,276 --> 00:03:32,277 know that something is happening. 60 00:03:32,279 --> 00:03:35,213 Something's up, it's new, and it's different. 61 00:03:38,351 --> 00:03:41,753 This combination of a long gravitational wave signal 62 00:03:41,755 --> 00:03:45,890 and a Blaze of gamma rays... 63 00:03:45,892 --> 00:03:48,359 Acts as a beacon for astronomers. 64 00:03:51,031 --> 00:03:52,897 When they saw this event, 65 00:03:52,899 --> 00:03:55,099 they sent out a worldwide alert 66 00:03:55,101 --> 00:03:57,301 to astronomers across the globe, saying, 67 00:03:57,303 --> 00:04:00,371 "hey, we saw something interesting, 68 00:04:00,373 --> 00:04:02,974 and it came from a particular patch of sky. 69 00:04:02,976 --> 00:04:05,109 Then, all the chatter started 70 00:04:05,111 --> 00:04:07,111 amongst the astronomical community, 71 00:04:07,113 --> 00:04:09,447 and everyone starting pointing their telescopes 72 00:04:09,449 --> 00:04:12,516 at this one part of the sky. 73 00:04:12,518 --> 00:04:15,119 Within hours, thousands of astronomers 74 00:04:15,121 --> 00:04:18,189 and physicists across the globe are frantically 75 00:04:18,191 --> 00:04:22,393 collecting data on this mysterious event. 76 00:04:22,395 --> 00:04:24,596 There is not just the gravitational waves, 77 00:04:24,598 --> 00:04:26,197 there is not just the gamma rays. 78 00:04:26,199 --> 00:04:28,533 There's a visible light, there's infrared light, 79 00:04:28,535 --> 00:04:30,335 there's ultraviolet light. 80 00:04:30,337 --> 00:04:33,604 And all these signals together tell us a story. 81 00:04:33,606 --> 00:04:35,807 And this was the very first time 82 00:04:35,809 --> 00:04:38,476 we've seen these two multiple messengers at once ... 83 00:04:38,478 --> 00:04:40,945 gravitational waves and regular light. 84 00:04:40,947 --> 00:04:43,948 So, that was a groundbreaking moment for astronomy. 85 00:04:47,621 --> 00:04:49,421 Scientists realize 86 00:04:49,423 --> 00:04:52,424 this isn't another black-hole collision. 87 00:04:52,426 --> 00:04:55,360 This is something different. 88 00:04:55,362 --> 00:04:57,962 When you see an explosion in the universe, 89 00:04:57,964 --> 00:05:00,498 there aren't exactly a lot of candidates. 90 00:05:00,500 --> 00:05:03,568 There's not a lot of things in the universe that blow up. 91 00:05:05,772 --> 00:05:09,574 But the length of the signal is the smoking gun. 92 00:05:09,576 --> 00:05:12,777 The collision of two black holes was quick. 93 00:05:12,779 --> 00:05:18,716 This one was the longer, slower, death end-spiral 94 00:05:18,718 --> 00:05:20,919 of two neutron stars. 95 00:05:20,921 --> 00:05:24,723 Spiraling in, closer and closer, speeding up. 96 00:05:24,725 --> 00:05:26,457 And then, when they finally collide, 97 00:05:26,459 --> 00:05:28,926 when they finally touch, releasing a tremendous 98 00:05:28,928 --> 00:05:31,830 amount of energy into the surrounding system. 99 00:05:34,200 --> 00:05:37,068 The collision throws up huge clouds of matter, 100 00:05:37,070 --> 00:05:40,405 which may have slowed down the light very slightly. 101 00:05:40,407 --> 00:05:42,674 The light and gravitational waves 102 00:05:42,676 --> 00:05:46,010 travel for 130 million years, 103 00:05:46,012 --> 00:05:50,348 arriving at earth almost simultaneously. 104 00:05:50,350 --> 00:05:54,886 It's the first time astronomers see neutron stars collide. 105 00:05:54,888 --> 00:05:57,554 They call it a "kilonova." 106 00:05:57,556 --> 00:06:00,124 And this spectacular cosmic event 107 00:06:00,126 --> 00:06:02,828 doesn't just release energy. 108 00:06:02,830 --> 00:06:05,096 The aftermath of this neutron-star collision, 109 00:06:05,098 --> 00:06:08,099 this kilonova, created a tremendous amount of debris, 110 00:06:08,101 --> 00:06:10,101 which blasted out into space. 111 00:06:10,103 --> 00:06:12,103 And this may finally have provided us 112 00:06:12,105 --> 00:06:14,772 the evidence of where some very special 113 00:06:14,774 --> 00:06:17,041 heavy elements are created. 114 00:06:17,043 --> 00:06:21,979 Through the destruction of a neutron star comes the seeds 115 00:06:21,981 --> 00:06:25,050 for the essential ingredients of life itself. 116 00:06:25,052 --> 00:06:28,720 We breathe oxygen molecules ... O2. 117 00:06:28,722 --> 00:06:30,855 Water is hydrogen and oxygen. 118 00:06:30,857 --> 00:06:34,325 Most of our body is made up of carbon compounds 119 00:06:34,327 --> 00:06:36,127 that include nitrogen, phosphorus. 120 00:06:36,129 --> 00:06:38,796 One of the big questions in science 121 00:06:38,798 --> 00:06:41,332 over the history of humanity has been, 122 00:06:41,334 --> 00:06:44,201 "what are the origins of these elements?" 123 00:06:44,203 --> 00:06:48,473 And it turns out that neutron stars play a critical role 124 00:06:48,475 --> 00:06:50,975 in creating many of the heavy elements. 125 00:06:54,280 --> 00:06:59,817 Most of the elements on earth are made in stars. 126 00:06:59,819 --> 00:07:02,419 But how the heaviest elements are made 127 00:07:02,421 --> 00:07:06,091 has been one of science's longest-running mysteries. 128 00:07:08,094 --> 00:07:09,961 For a long time, we knew there was a problem 129 00:07:09,963 --> 00:07:11,562 with making these heavier atoms ... 130 00:07:11,564 --> 00:07:15,033 things like gold and platinum, all the way out towards uranium. 131 00:07:15,035 --> 00:07:16,700 And really, the most energetic thing we had 132 00:07:16,702 --> 00:07:19,103 in the universe was supernova explosions. 133 00:07:19,105 --> 00:07:22,173 So, they had to be created somehow in supernovas. 134 00:07:22,175 --> 00:07:25,309 But when scientists ran computer simulations, 135 00:07:25,311 --> 00:07:29,948 virtual supernovas failed to forge these oversized atoms. 136 00:07:33,186 --> 00:07:37,188 In 2016, astronomer edo berger explained 137 00:07:37,190 --> 00:07:39,725 a potential solution to the mystery. 138 00:07:43,463 --> 00:07:45,330 Berger: If you open any one of these books, 139 00:07:45,332 --> 00:07:48,399 and flip to the page that tells you where gold came from, 140 00:07:48,401 --> 00:07:51,136 it will tell you that gold came from supernova explosions. 141 00:07:57,210 --> 00:08:01,145 But it was becoming clear that the textbooks were out of date. 142 00:08:06,219 --> 00:08:08,819 berger: To form heavy elements requires a lot of neutrons, 143 00:08:08,821 --> 00:08:11,222 and so, another possible theory was that 144 00:08:11,224 --> 00:08:13,958 the heaviest elements were produced in the mergers 145 00:08:13,960 --> 00:08:17,294 of two neutron stars in a binary system. 146 00:08:17,296 --> 00:08:19,864 But at the time, no one had actually seen 147 00:08:19,866 --> 00:08:21,899 a neutron-star collision. 148 00:08:21,901 --> 00:08:24,168 It was difficult to convince the community 149 00:08:24,170 --> 00:08:26,304 that this was a potential channel 150 00:08:26,306 --> 00:08:28,506 for the production of heavy elements. 151 00:08:28,508 --> 00:08:31,042 The proof is to actually see this process 152 00:08:31,044 --> 00:08:32,310 happening in the universe. 153 00:08:34,313 --> 00:08:36,247 The 2017 kilonova 154 00:08:36,249 --> 00:08:38,849 provides the perfect opportunity. 155 00:08:38,851 --> 00:08:42,720 It generates thousands of hours of data. 156 00:08:42,722 --> 00:08:45,257 Scientists notice a pattern ... 157 00:08:45,259 --> 00:08:50,595 subtle changes in the color of the kilonova remnants. 158 00:08:50,597 --> 00:08:53,397 In space, when you have an event that is very bright, 159 00:08:53,399 --> 00:08:54,932 it emits a certain amount of light, 160 00:08:54,934 --> 00:08:56,668 and it emits it at certain wavelengths ... 161 00:08:56,670 --> 00:08:59,136 what we think of as colors. 162 00:08:59,138 --> 00:09:02,073 Different colors in a pyrotechnics display 163 00:09:02,075 --> 00:09:05,610 indicate the use of different chemicals in fireworks. 164 00:09:05,612 --> 00:09:09,080 In the same way, scientists can uncover the elements 165 00:09:09,082 --> 00:09:14,018 in the kilonova by the colors in the explosion. 166 00:09:14,020 --> 00:09:17,889 As the kilonova turns red, they realize it's the result 167 00:09:17,891 --> 00:09:20,024 of newly-created heavy elements 168 00:09:20,026 --> 00:09:23,160 starting to absorb blue light. 169 00:09:23,162 --> 00:09:25,496 As we watched this remnant change ... 170 00:09:25,498 --> 00:09:28,699 the explosion change in color, expand and cool ... 171 00:09:28,701 --> 00:09:31,602 we could estimate what sort of elements were being produced. 172 00:09:33,907 --> 00:09:36,107 The light from the debris shifts 173 00:09:36,109 --> 00:09:39,844 from blue and Violet to red and infrared. 174 00:09:39,846 --> 00:09:42,580 The color change provides clues 175 00:09:42,582 --> 00:09:46,050 about the presence of certain heavy metals. 176 00:09:54,127 --> 00:09:57,061 well, this neutron-star collision, this kilonova, 177 00:09:57,063 --> 00:10:00,197 produced brightness and a color spectrum 178 00:10:00,199 --> 00:10:03,601 that are consistent with models of predictions 179 00:10:03,603 --> 00:10:05,737 that produce gold and platinum. 180 00:10:08,274 --> 00:10:11,141 This model is called "the r-process," 181 00:10:11,143 --> 00:10:14,145 short for "rapid neutron capture." 182 00:10:14,147 --> 00:10:16,480 That is a bit of a complicated term 183 00:10:16,482 --> 00:10:19,951 that describes how we make atoms heavier than iron. 184 00:10:19,953 --> 00:10:22,220 You need a really neutron-rich environment. 185 00:10:22,222 --> 00:10:25,022 And as you might imagine, a neutron-star collision 186 00:10:25,024 --> 00:10:27,625 is a very neutron-rich environment. 187 00:10:27,627 --> 00:10:29,426 If these models are correct ... 188 00:10:29,428 --> 00:10:31,562 and this blows me away ... 189 00:10:31,564 --> 00:10:33,497 this collision, this kilonova, 190 00:10:33,499 --> 00:10:37,702 produced several dozen times the mass of the earth 191 00:10:37,704 --> 00:10:39,770 in just gold. 192 00:10:46,379 --> 00:10:49,846 The 2017 kilonova not only reveals 193 00:10:49,848 --> 00:10:52,115 the origin of key elements, 194 00:10:52,117 --> 00:10:55,786 it sheds light on the neutron star's interior ... 195 00:10:55,788 --> 00:10:58,922 the strongest material in the universe 196 00:10:58,924 --> 00:11:00,858 creating a magnetic field 197 00:11:00,860 --> 00:11:04,328 a trillion times greater than that of earth. 198 00:11:23,016 --> 00:11:28,219 Two neutron stars caught in a death spiral. 199 00:11:28,221 --> 00:11:32,356 This massive kilonova explosion not only sheds light 200 00:11:32,358 --> 00:11:34,292 on the creation of heavy elements, 201 00:11:34,294 --> 00:11:36,693 such as gold and platinum, 202 00:11:36,695 --> 00:11:39,964 it also provides scientists with a unique insight 203 00:11:39,966 --> 00:11:44,235 into one of the most mysterious objects in the universe. 204 00:11:44,237 --> 00:11:47,304 Trying to imagine what a neutron star is really like 205 00:11:47,306 --> 00:11:49,173 really challenges our imagination. 206 00:11:49,175 --> 00:11:51,442 It also challenges our theoretical physics. 207 00:11:51,444 --> 00:11:53,910 We have to go to our computer models, our mathematics, 208 00:11:53,912 --> 00:11:57,848 to have some estimate of what this might be like. 209 00:11:57,850 --> 00:12:00,518 Now, scientists don't have to rely 210 00:12:00,520 --> 00:12:01,853 on their imaginations. 211 00:12:03,255 --> 00:12:06,924 They can use hard data from the kilonova 212 00:12:06,926 --> 00:12:10,061 to work out what makes neutron stars tick. 213 00:12:14,600 --> 00:12:16,601 There's so much information we got from observing 214 00:12:16,603 --> 00:12:20,071 that one single event, that one colliding neutron star pair. 215 00:12:20,073 --> 00:12:22,673 Now, for the first time, we have an accurate estimate 216 00:12:22,675 --> 00:12:25,009 of the mass of a neutron star, and the diameter. 217 00:12:25,011 --> 00:12:26,811 We can finally begin to piece together 218 00:12:26,813 --> 00:12:30,347 how neutron stars really work. 219 00:12:30,349 --> 00:12:34,485 They calculate the diameter is just 12.4 miles, 220 00:12:34,487 --> 00:12:39,289 1 mile less than the length of Manhattan. 221 00:12:39,291 --> 00:12:41,693 Nailing down any physical characteristic 222 00:12:41,695 --> 00:12:43,028 is really important. 223 00:12:43,030 --> 00:12:44,428 And if there's gonna be one, 224 00:12:44,430 --> 00:12:47,030 the radius is a big one, because from there, 225 00:12:47,032 --> 00:12:48,766 if you know the mass, you can get the density. 226 00:12:48,768 --> 00:12:50,434 And if you know the overall density, 227 00:12:50,436 --> 00:12:52,170 you can start to figure out what the layering 228 00:12:52,172 --> 00:12:54,071 inside of a neutron star is like. 229 00:12:58,144 --> 00:13:01,645 For physicists, the interior of a neutron star 230 00:13:01,647 --> 00:13:05,983 is one of the most intriguing places in the universe. 231 00:13:05,985 --> 00:13:07,651 Bullock: You have to realize that the conditions 232 00:13:07,653 --> 00:13:09,720 inside a neutron star are very, very different 233 00:13:09,722 --> 00:13:11,789 than the conditions that exist here on earth. 234 00:13:11,791 --> 00:13:13,924 We're talking about material that's so dense 235 00:13:13,926 --> 00:13:17,194 that even the nuclei of atoms can't hold together. 236 00:13:17,196 --> 00:13:19,397 With a neutron star, you're taking something 237 00:13:19,399 --> 00:13:21,733 that weighs more than the sun, 238 00:13:21,735 --> 00:13:25,536 and compressing it down to be smaller than a city. 239 00:13:25,538 --> 00:13:28,339 It's so dense that, if you tried to put it on the ground, 240 00:13:28,341 --> 00:13:30,208 it would fall right through the earth. 241 00:13:32,211 --> 00:13:35,279 High density means high gravity ... 242 00:13:35,281 --> 00:13:40,084 gravity 200 billion times greater than on earth. 243 00:13:40,086 --> 00:13:41,685 Imagine climbing up on a table on the surface 244 00:13:41,687 --> 00:13:43,554 of a neutron star and jumping off. 245 00:13:43,556 --> 00:13:45,689 You're gonna just get flattened instantly, 246 00:13:45,691 --> 00:13:48,291 and just spread out on that surface. 247 00:13:48,293 --> 00:13:52,696 So, don't even think about trying to do push-ups. 248 00:13:52,698 --> 00:13:54,498 Added to the intense gravity 249 00:13:54,500 --> 00:13:57,234 are hugely powerful magnetic fields, 250 00:13:57,236 --> 00:13:59,303 awesome X-ray radiation, 251 00:13:59,305 --> 00:14:02,974 electric fields 30 million times more powerful 252 00:14:02,976 --> 00:14:04,976 than lightning bolts, 253 00:14:04,978 --> 00:14:09,112 and blizzards of high-energy particles. 254 00:14:09,114 --> 00:14:13,084 This isn't a good neighborhood for a space traveler. 255 00:14:16,055 --> 00:14:19,056 Sutter: If you were to find yourself in the vicinity 256 00:14:19,058 --> 00:14:22,593 of a neutron star, it's gonna be bad news. 257 00:14:22,595 --> 00:14:24,595 First, you would be torn apart 258 00:14:24,597 --> 00:14:27,264 by the incredibly strong magnetic fields. 259 00:14:27,266 --> 00:14:32,204 Then, the X-ray radiation would blast you to a crisp. 260 00:14:32,206 --> 00:14:34,070 And as it pulled you closer, 261 00:14:34,072 --> 00:14:36,473 its intense gravity would stretch out 262 00:14:36,475 --> 00:14:40,010 your atoms and molecules into a long, thin stream. 263 00:14:40,012 --> 00:14:42,947 You would build your speed faster and faster, 264 00:14:42,949 --> 00:14:45,950 and then, you would finally impact the surface, 265 00:14:45,952 --> 00:14:47,686 splatter across it. 266 00:14:47,688 --> 00:14:50,755 And that process would release as much energy 267 00:14:50,757 --> 00:14:51,822 as a nuclear bomb. 268 00:14:54,894 --> 00:14:58,095 If I had the choice between falling into a neutron star 269 00:14:58,097 --> 00:15:01,298 versus a black hole, I think I'd pick the black hole. 270 00:15:01,300 --> 00:15:03,501 'Cause I don't really feel like being torn apart 271 00:15:03,503 --> 00:15:06,036 by a magnetic field and blasted with x-rays. 272 00:15:10,509 --> 00:15:15,045 On a cosmic scale, neutron stars may be pint-sized, 273 00:15:15,047 --> 00:15:17,715 but they sure pack a serious punch. 274 00:15:17,717 --> 00:15:20,317 The secret to all this pent-up power 275 00:15:20,319 --> 00:15:24,855 is what's going on below the surface. 276 00:15:24,857 --> 00:15:27,391 Armed with the new kilonova data, 277 00:15:27,393 --> 00:15:29,126 we can now take a virtual journey 278 00:15:29,128 --> 00:15:31,795 into the heart of a neutron star. 279 00:15:31,797 --> 00:15:36,133 First, we must pass through its atmosphere. 280 00:15:36,135 --> 00:15:37,467 Now, it's not like the earth's atmosphere, 281 00:15:37,469 --> 00:15:39,269 which goes up, like, a 100 miles. 282 00:15:39,271 --> 00:15:42,673 On a neutron star, the atmosphere is about this deep, 283 00:15:42,675 --> 00:15:47,945 and it's extremely dense compared to the air around us. 284 00:15:47,947 --> 00:15:52,549 Below the compressed atmosphere is a crust of ionized iron, 285 00:15:52,551 --> 00:15:54,951 a mixture of crystal iron nuclei, 286 00:15:54,953 --> 00:15:58,289 and free-flowing iron electrons. 287 00:15:58,291 --> 00:16:00,357 Now, the gravity's so strong 288 00:16:00,359 --> 00:16:02,560 that it's almost perfectly smooth. 289 00:16:02,562 --> 00:16:04,028 The biggest mountains on the surface 290 00:16:04,030 --> 00:16:06,431 are gonna be less than a quarter of an inch high. 291 00:16:06,433 --> 00:16:11,902 A quarter-inch mountain range may sound odd... 292 00:16:11,904 --> 00:16:16,207 But things get even stranger as we go below the surface. 293 00:16:18,311 --> 00:16:22,279 This is home to the strongest material in the universe. 294 00:16:25,451 --> 00:16:31,522 It's so weird, scientists liken it to nuclear pasta. 295 00:16:31,524 --> 00:16:34,525 Sutter: As we dive beneath the crust of a neutron star, 296 00:16:34,527 --> 00:16:37,861 the neutrons themselves start to glue themselves together 297 00:16:37,863 --> 00:16:39,730 into exotic shapes. 298 00:16:39,732 --> 00:16:45,002 First, they form clumps that look something like gnocchi, 299 00:16:45,004 --> 00:16:48,072 then, deeper, the gnocchi glue themselves together 300 00:16:48,074 --> 00:16:52,142 to form long strands that look like spaghetti. 301 00:16:52,144 --> 00:16:54,678 Even deeper, the spaghetti fuse together 302 00:16:54,680 --> 00:16:58,148 to form sheets of lasagna. 303 00:16:58,150 --> 00:17:01,151 And then, finally, the lasagna fuse together 304 00:17:01,153 --> 00:17:05,689 to become a uniform mass, but with holes in it. 305 00:17:05,691 --> 00:17:08,159 So, it looks like penne. 306 00:17:08,161 --> 00:17:11,629 This is pasta, nuclear style, 307 00:17:11,631 --> 00:17:12,829 simmering at a temperature 308 00:17:12,831 --> 00:17:15,632 of over one million degrees fahrenheit. 309 00:17:15,634 --> 00:17:19,436 Extreme gravity bends, squeezes, stretches, 310 00:17:19,438 --> 00:17:22,372 and buckles neutrons, creating a material 311 00:17:22,374 --> 00:17:26,710 100,000 billion times denser than iron. 312 00:17:26,712 --> 00:17:30,447 But the journey gets even more extreme. 313 00:17:30,449 --> 00:17:34,251 Even deeper is more mysterious and harder to understand. 314 00:17:34,253 --> 00:17:36,320 The core of a neutron star ... 315 00:17:36,322 --> 00:17:39,123 which is very far away from these layers, 316 00:17:39,125 --> 00:17:41,191 which we call the "nuclear pasta" ... 317 00:17:41,193 --> 00:17:44,395 is perhaps the most exotic form of matter. 318 00:17:44,397 --> 00:17:48,665 So exotic it might be the last bastion of matter 319 00:17:48,667 --> 00:17:52,937 before complete gravitational collapse into a black hole. 320 00:17:54,941 --> 00:17:57,274 Data from NASA's chandra observatory 321 00:17:57,276 --> 00:18:00,678 suggests the core is made up of a super fluid ... 322 00:18:00,680 --> 00:18:04,414 a bizarre friction-free state of matter. 323 00:18:04,416 --> 00:18:07,151 Similar super fluids produced in the lab 324 00:18:07,153 --> 00:18:09,086 exhibit strange properties, 325 00:18:09,088 --> 00:18:11,822 such as the ability to flow upwards 326 00:18:11,824 --> 00:18:15,693 and escape airtight containers. 327 00:18:15,695 --> 00:18:18,028 Although our knowledge of the star's interior 328 00:18:18,030 --> 00:18:20,230 is still hazy, there's not mystery 329 00:18:20,232 --> 00:18:22,432 about its dazzling birth. 330 00:18:22,434 --> 00:18:26,503 Forged into life during the most spectacular event 331 00:18:26,505 --> 00:18:28,505 the universe has to offer ... 332 00:18:28,507 --> 00:18:31,910 the explosive death of a massive star. 333 00:18:48,127 --> 00:18:50,127 Neutron stars ... 334 00:18:50,129 --> 00:18:56,800 Manhattan-sized, but with a mass twice that of our sun. 335 00:18:56,802 --> 00:19:02,806 So dense a teaspoon of their matter weighs a billion tons. 336 00:19:02,808 --> 00:19:07,077 Mind-blowing objects that arrive with a bang. 337 00:19:07,079 --> 00:19:09,013 Neutron stars spark into life 338 00:19:09,015 --> 00:19:11,081 amid the death of their parent star. 339 00:19:11,083 --> 00:19:13,684 They're the ultimate story of resurrection, 340 00:19:13,686 --> 00:19:16,353 or of life from death. 341 00:19:16,355 --> 00:19:20,490 It's all part of a cosmic cycle. 342 00:19:20,492 --> 00:19:24,762 Stars are born from giant clouds of very cold gas. 343 00:19:24,764 --> 00:19:27,866 Those clouds collapse under their own gravity, 344 00:19:27,868 --> 00:19:31,034 and the density of the core at the center of the collapse 345 00:19:31,036 --> 00:19:32,169 starts to increase. 346 00:19:37,309 --> 00:19:41,178 A star is a huge nuclear fusion reactor. 347 00:19:41,180 --> 00:19:43,780 The force of its gravity is so powerful 348 00:19:43,782 --> 00:19:45,582 that it fuses atoms together 349 00:19:45,584 --> 00:19:50,454 to make progressively heavier and heavier elements. 350 00:19:50,456 --> 00:19:53,657 The star fuses hydrogen into helium. 351 00:19:53,659 --> 00:19:56,860 Once it exhausts its hydrogen, then, if it's massive enough, 352 00:19:56,862 --> 00:19:59,196 it can start fusing helium at its core. 353 00:20:01,734 --> 00:20:04,401 Fusion continues, forming carbon, 354 00:20:04,403 --> 00:20:10,474 oxygen, nitrogen, all the way up to iron. 355 00:20:10,476 --> 00:20:12,743 Once a star has iron in the core, 356 00:20:12,745 --> 00:20:14,678 it's almost like you've poisoned it, 357 00:20:14,680 --> 00:20:18,414 because this extinguishes the nuclear reactions 358 00:20:18,416 --> 00:20:19,749 in the core of the star. 359 00:20:19,751 --> 00:20:23,954 You fuse something into iron, and you get no energy. 360 00:20:23,956 --> 00:20:25,756 All of a sudden, there's nothing to support 361 00:20:25,758 --> 00:20:27,091 the crush of gravity. 362 00:20:27,093 --> 00:20:28,759 No radiation pressure pushing out 363 00:20:28,761 --> 00:20:32,697 means no pressure keeping the outer regions from falling in, 364 00:20:32,699 --> 00:20:34,565 and that's what they do. 365 00:20:34,567 --> 00:20:37,767 As the star collapses in its death throes, 366 00:20:37,769 --> 00:20:41,171 its core becomes the wildest, craziest, 367 00:20:41,173 --> 00:20:45,375 and freakiest pressure cooker in the whole universe. 368 00:20:47,513 --> 00:20:50,046 The ingredients are all in place. 369 00:20:50,048 --> 00:20:54,853 It's time to start cooking up a neutron star. 370 00:20:54,855 --> 00:20:57,654 If we were to scale up an atomic nucleus 371 00:20:57,656 --> 00:20:59,522 to be the size of a baseball, 372 00:20:59,524 --> 00:21:03,594 in a normal atom, the nearest electron would be 373 00:21:03,596 --> 00:21:05,530 way over in those trees, 374 00:21:05,532 --> 00:21:07,664 but in the extreme conditions that lead to 375 00:21:07,666 --> 00:21:09,867 the formation of a neutron star, 376 00:21:09,869 --> 00:21:13,937 those electrons can be pushed closer to the nucleus. 377 00:21:13,939 --> 00:21:17,073 They can come zipping in from any direction. 378 00:21:17,075 --> 00:21:19,943 And if the temperatures and pressures are high enough, 379 00:21:19,945 --> 00:21:22,012 they can even strike the nucleus 380 00:21:22,014 --> 00:21:24,881 and enter it, and they can hit a proton. 381 00:21:24,883 --> 00:21:29,419 And when they do, they become converted into more neutrons. 382 00:21:29,421 --> 00:21:32,023 So, in the formation of one of these objects, 383 00:21:32,025 --> 00:21:34,424 the protons and electrons disappear, 384 00:21:34,426 --> 00:21:37,360 and you're left with almost entirely pure neutrons, 385 00:21:37,362 --> 00:21:40,430 with nothing to stop them from cramming together 386 00:21:40,432 --> 00:21:43,300 and filling up this entire baseball 387 00:21:43,302 --> 00:21:48,905 with neutrons leading to incredibly high densities. 388 00:21:48,907 --> 00:21:50,307 With the sea of electrons 389 00:21:50,309 --> 00:21:52,776 now absorbed in the atomic nuclei, 390 00:21:52,778 --> 00:21:57,714 the matter in the stars can now press together a lot tighter. 391 00:21:57,716 --> 00:22:00,917 It's like squeezing 300 million tons of mass 392 00:22:00,919 --> 00:22:04,254 into a single sugar cube. 393 00:22:04,256 --> 00:22:06,056 As the star collapses, 394 00:22:06,058 --> 00:22:09,126 enormous amounts of gas fall towards the core. 395 00:22:11,863 --> 00:22:16,399 The core is small in size, but huge in mass. 396 00:22:16,401 --> 00:22:19,203 Billions of tons of gas bounce off of it, 397 00:22:19,205 --> 00:22:22,672 then erupt into the biggest fireworks display 398 00:22:22,674 --> 00:22:25,542 in the cosmos... 399 00:22:25,544 --> 00:22:28,145 A supernova. 400 00:22:28,147 --> 00:22:29,412 It's massive. 401 00:22:29,414 --> 00:22:30,546 It's bright. 402 00:22:30,548 --> 00:22:31,815 It's imposing. 403 00:22:31,817 --> 00:22:34,951 Supernova are among the most dramatic events 404 00:22:34,953 --> 00:22:36,419 to happen in the universe. 405 00:22:36,421 --> 00:22:38,088 A single star dying ... 406 00:22:38,090 --> 00:22:43,061 one star dying ... can outshine an entire galaxy. 407 00:22:46,965 --> 00:22:49,432 And arising out of this cataclysm, 408 00:22:49,434 --> 00:22:52,836 a new and very strange cosmic entity. 409 00:22:55,841 --> 00:22:58,775 When the smoke finally clears from the supernova explosion, 410 00:22:58,777 --> 00:23:01,445 you're left with one of the most real, fascinating, 411 00:23:01,447 --> 00:23:04,580 unbelievable monsters of the entire universe. 412 00:23:04,582 --> 00:23:06,183 Humans have been witnessing supernovas 413 00:23:06,185 --> 00:23:07,851 for thousands of years, 414 00:23:07,853 --> 00:23:10,654 but we're only now just starting to understand 415 00:23:10,656 --> 00:23:13,457 what we've truly been witnessing ... 416 00:23:13,459 --> 00:23:17,327 the births of neutron stars. 417 00:23:17,329 --> 00:23:20,463 But while supernovas are big and bright, 418 00:23:20,465 --> 00:23:23,066 neutron stars are small, 419 00:23:23,068 --> 00:23:26,202 and many don't even give off light. 420 00:23:26,204 --> 00:23:30,141 So, how many neutron stars are out there? 421 00:23:30,143 --> 00:23:33,677 We know of about 2,000 neutron stars in our galaxy, 422 00:23:33,679 --> 00:23:35,279 but there probably are many, many, more. 423 00:23:35,281 --> 00:23:38,148 I'm talking about tens of millions in the milky way alone, 424 00:23:38,150 --> 00:23:42,419 and certainly billions throughout the universe. 425 00:23:42,421 --> 00:23:48,291 Neutron stars may be small, but some give themselves away, 426 00:23:48,293 --> 00:23:51,762 shooting beams across the universe ... 427 00:23:51,764 --> 00:23:56,967 unmistakable, pulsing strobes of a cosmic lighthouse. 428 00:24:16,054 --> 00:24:20,524 Our knowledge of neutron stars is expanding fast. 429 00:24:23,128 --> 00:24:25,263 But we didn't even know they existed 430 00:24:25,265 --> 00:24:28,765 until a lucky discovery just over 50 years ago. 431 00:24:30,803 --> 00:24:34,003 Sutter: Cambridge, the mullard radio observatory, 432 00:24:34,005 --> 00:24:35,939 Jocelyn bell, grad student, 433 00:24:35,941 --> 00:24:39,475 operating the new radio telescope. 434 00:24:39,477 --> 00:24:42,612 Scanning the sky, doing all sorts of cool astronomy stuff, 435 00:24:42,614 --> 00:24:48,017 and sees what she calls "a bit of scruff" in the data. 436 00:24:48,019 --> 00:24:49,419 This scruff is a short 437 00:24:49,421 --> 00:24:52,756 but constantly repeating burst of radiation 438 00:24:52,758 --> 00:24:57,027 originating 1,000 light years from earth. 439 00:24:57,029 --> 00:25:00,296 It's so stable and regular that bell is convinced 440 00:25:00,298 --> 00:25:02,900 there's a fault with her telescope. 441 00:25:02,902 --> 00:25:04,901 She returns to that spot, 442 00:25:04,903 --> 00:25:09,106 and finds a repeating, regular signal ... 443 00:25:09,108 --> 00:25:14,710 a single point in the sky that is flashing at us continually, 444 00:25:14,712 --> 00:25:17,514 saying "hi. Hi. Hi." 445 00:25:17,516 --> 00:25:19,182 Blip, blip, blip. 446 00:25:19,184 --> 00:25:21,518 Boom, boom, boom. 447 00:25:21,520 --> 00:25:23,453 Pulse, pulse, pulse. 448 00:25:23,455 --> 00:25:25,455 Nothing that we know of in the universe, 449 00:25:25,457 --> 00:25:30,059 has such a steady, perfectly-spaced in time, pulse. 450 00:25:30,061 --> 00:25:34,265 It seemed so perfect that it must have been artificial. 451 00:25:34,267 --> 00:25:37,734 It looks like someone is making that, 452 00:25:37,736 --> 00:25:41,671 but it turns out, it's not a person, but a thing. 453 00:25:41,673 --> 00:25:44,475 What she discovered was called a "pulsar." 454 00:25:47,346 --> 00:25:50,013 A pulsar is a type of rapidly spinning 455 00:25:50,015 --> 00:25:51,281 neutron star. 456 00:25:54,086 --> 00:25:57,954 Neutron stars had been theorized in the 1930s, 457 00:25:57,956 --> 00:26:01,892 but were thought to be too faint to be detected. 458 00:26:01,894 --> 00:26:06,429 Neutron stars were hypothesized to exist, 459 00:26:06,431 --> 00:26:09,365 but not really taken seriously. 460 00:26:09,367 --> 00:26:11,902 It was just a, "oh, that's cute. 461 00:26:11,904 --> 00:26:14,404 Maybe they're out there, but probably not." 462 00:26:15,641 --> 00:26:17,440 The signal bell detected 463 00:26:17,442 --> 00:26:21,445 seemed like something from science fiction. 464 00:26:21,447 --> 00:26:24,180 No one had ever seen this in astronomy before, 465 00:26:24,182 --> 00:26:28,319 and some people even speculated that it was an alien signal. 466 00:26:28,321 --> 00:26:30,720 She even called them "lgm objects" ... 467 00:26:30,722 --> 00:26:33,590 "little green men." 468 00:26:33,592 --> 00:26:36,093 But then, bell found a second signal. 469 00:26:38,931 --> 00:26:42,132 Little green men went back to being fiction, 470 00:26:42,134 --> 00:26:45,868 and pulsars became science fact. 471 00:26:45,870 --> 00:26:48,137 The discovery of pulsars came out of the blue. 472 00:26:48,139 --> 00:26:49,739 Nobody was expecting this. 473 00:26:49,741 --> 00:26:51,876 So, it was an amazing breakthrough ... 474 00:26:51,878 --> 00:26:53,076 really important. 475 00:26:56,348 --> 00:27:00,750 Pulsars pulse because they are born to spin. 476 00:27:00,752 --> 00:27:04,821 They burst into life as their parent star collapses 477 00:27:04,823 --> 00:27:06,356 during a supernova. 478 00:27:08,627 --> 00:27:10,961 Any object at all that is undergoing 479 00:27:10,963 --> 00:27:13,095 any sort of compression event, 480 00:27:13,097 --> 00:27:16,299 if it has any initial angular momentum at all, 481 00:27:16,301 --> 00:27:20,503 it will eventually end up spinning. 482 00:27:20,505 --> 00:27:24,508 As the star shrinks, it spins faster and faster. 483 00:27:26,511 --> 00:27:30,647 They spin so quickly because the earth-sized core 484 00:27:30,649 --> 00:27:32,048 of a massive star 485 00:27:32,050 --> 00:27:35,252 collapsed to something as small as a city. 486 00:27:35,254 --> 00:27:39,456 So, because the size of the object became so much smaller, 487 00:27:39,458 --> 00:27:44,127 the rate of spin had to increase by a tremendous amount. 488 00:27:44,129 --> 00:27:47,464 Neutron stars can spin really, really, fast. 489 00:27:47,466 --> 00:27:49,932 Their surface is moving so fast. 490 00:27:49,934 --> 00:27:53,670 It's moving at about 20% the speed of light, in some cases. 491 00:27:53,672 --> 00:27:57,006 Sutter: So, if you were to get on the neutron star ride ... 492 00:27:57,008 --> 00:28:01,077 no pregnant women, no bad backs, no heart issues, 493 00:28:01,079 --> 00:28:03,680 keep your arms and legs inside the ride at all times, 494 00:28:03,682 --> 00:28:05,950 because they are about to be obliterated. 495 00:28:07,886 --> 00:28:13,223 And as they spin, they generate flashing beams of energy. 496 00:28:13,225 --> 00:28:15,625 This beam is like a lighthouse beam. 497 00:28:15,627 --> 00:28:18,962 You see these periodic flashes many times per second. 498 00:28:18,964 --> 00:28:20,563 So, every time you see it ... 499 00:28:20,565 --> 00:28:23,834 beam, beam, beam. 500 00:28:23,836 --> 00:28:26,903 These beams are the pulsar's calling card. 501 00:28:26,905 --> 00:28:29,639 They're generated by the elemental chaos 502 00:28:29,641 --> 00:28:32,241 raging inside a neutron star. 503 00:28:32,243 --> 00:28:34,110 Although the star is predominantly 504 00:28:34,112 --> 00:28:35,978 a ball of neutrons, 505 00:28:35,980 --> 00:28:39,716 the crust is sprinkled with protons and electrons, 506 00:28:39,718 --> 00:28:41,918 spinning hundreds of times a second, 507 00:28:41,920 --> 00:28:44,621 generating an incredible magnetic field. 508 00:28:46,391 --> 00:28:48,191 And with this strong magnetic field, 509 00:28:48,193 --> 00:28:50,260 you can create strong electric fields. 510 00:28:50,262 --> 00:28:51,994 And the electric and magnetic fields 511 00:28:51,996 --> 00:28:55,665 can work off of each other and become radiation. 512 00:28:55,667 --> 00:29:01,337 These neutron stars send jets ... beams of radiation ... 513 00:29:01,339 --> 00:29:03,406 out of their spinning poles. 514 00:29:03,408 --> 00:29:05,942 And if their spinning pole is misaligned, 515 00:29:05,944 --> 00:29:07,545 if they're a little bit tilted, 516 00:29:07,547 --> 00:29:11,815 this beam will make circles, across the universe. 517 00:29:11,817 --> 00:29:14,550 And if we're in the path of one of these circles, 518 00:29:14,552 --> 00:29:17,086 we'll see a flash... 519 00:29:17,088 --> 00:29:18,287 A flash. 520 00:29:18,289 --> 00:29:19,889 Just like if you're on a ship, 521 00:29:19,891 --> 00:29:22,559 and you observe a distant lighthouse in a foggy night, 522 00:29:22,561 --> 00:29:26,630 you can see pulsars across the vast expanse of space 523 00:29:26,632 --> 00:29:30,166 because they are immensely powerful beams of light. 524 00:29:30,168 --> 00:29:33,570 But sometimes, pulsars get an extra push 525 00:29:33,572 --> 00:29:37,240 that accelerates the spin even more. 526 00:29:37,242 --> 00:29:39,376 The way you make it spin even faster 527 00:29:39,378 --> 00:29:42,578 is by subsequently dumping more material onto it. 528 00:29:42,580 --> 00:29:45,114 That's called "accretion," and you end up spinning it up 529 00:29:45,116 --> 00:29:47,183 even faster than it was already spinning. 530 00:29:47,185 --> 00:29:49,252 Like stellar vampires, 531 00:29:49,254 --> 00:29:51,589 pulsars are ready to suck the life 532 00:29:51,591 --> 00:29:54,958 out of any objects that stray too close. 533 00:29:54,960 --> 00:29:57,393 Gravity is bringing that material in, 534 00:29:57,395 --> 00:30:00,129 which means that any spin it has is accelerated. 535 00:30:00,131 --> 00:30:01,998 It spins faster and faster. 536 00:30:02,000 --> 00:30:04,200 These millisecond pulsars 537 00:30:04,202 --> 00:30:08,471 spin at around 700 revolutions per second. 538 00:30:08,473 --> 00:30:10,541 They are the ultimate kitchen blender ... 539 00:30:10,543 --> 00:30:14,844 they will chop, they will slice, they will even julienne fry. 540 00:30:17,549 --> 00:30:19,616 So, what stops neutron stars 541 00:30:19,618 --> 00:30:22,752 from simply tearing themselves apart? 542 00:30:22,754 --> 00:30:26,156 Neutron stars are incredibly exotic objects 543 00:30:26,158 --> 00:30:30,093 with immense, immense forces that bind them together, 544 00:30:30,095 --> 00:30:32,361 and so, they can be held rigid even against 545 00:30:32,363 --> 00:30:34,631 these incredibly fast rotation speeds. 546 00:30:38,369 --> 00:30:40,236 Bullock: They have incredibly strong gravity, 547 00:30:40,238 --> 00:30:42,172 and this is what allows them to hold together 548 00:30:42,174 --> 00:30:44,241 even though they're spinning around so fast. 549 00:30:47,312 --> 00:30:52,715 The speed of the spin is hard to imagine. 550 00:30:52,717 --> 00:30:54,917 On earth, a day is 24 hours long. 551 00:30:54,919 --> 00:30:59,922 On a neutron star, it's a 700th of a second long. 552 00:30:59,924 --> 00:31:01,591 Super-speeding pulsars 553 00:31:01,593 --> 00:31:03,859 are not the only weird stars 554 00:31:03,861 --> 00:31:06,395 that scientists are coming to grips with. 555 00:31:06,397 --> 00:31:08,798 There is one other type of neutron star, 556 00:31:08,800 --> 00:31:12,735 that has the most powerful magnetic field in the universe. 557 00:31:12,737 --> 00:31:17,040 This magnetic monster is called a "magnetar." 558 00:31:32,490 --> 00:31:35,692 Astronomers monitoring pulsing neutron stars 559 00:31:35,694 --> 00:31:38,561 have noticed something very odd. 560 00:31:38,563 --> 00:31:44,233 On very rare occasions, they can suddenly speed up. 561 00:31:44,235 --> 00:31:45,435 That's amazing. 562 00:31:45,437 --> 00:31:47,437 I mean, you've got this incredibly dense object, 563 00:31:47,439 --> 00:31:48,839 and suddenly, it's spinning faster. 564 00:31:48,841 --> 00:31:50,973 It happens...Instantly. 565 00:31:50,975 --> 00:31:52,775 They'll suddenly change frequency. 566 00:31:52,777 --> 00:31:56,112 It would take an amazing amount of power to do that. 567 00:31:56,114 --> 00:31:57,714 What's doing it? 568 00:31:57,716 --> 00:32:02,318 These sudden changes in speed are called "glitches." 569 00:32:02,320 --> 00:32:04,654 One leading idea for what causes these glitches 570 00:32:04,656 --> 00:32:07,257 is that the core material latches onto the crust, 571 00:32:07,259 --> 00:32:10,460 and this affects the way it can spin around. 572 00:32:10,462 --> 00:32:14,397 Excess material beneath the crust cracks it open, 573 00:32:14,399 --> 00:32:16,399 causing the glitch. 574 00:32:16,401 --> 00:32:20,336 This process releases a tremendous amount of radiation, 575 00:32:20,338 --> 00:32:24,874 a blast of x-rays, causes the face of the neutron star 576 00:32:24,876 --> 00:32:29,212 to rearrange itself, and for the rotation speed to change. 577 00:32:29,214 --> 00:32:31,881 But there's another possible explanation. 578 00:32:31,883 --> 00:32:36,152 Glitches could also be caused by starquakes. 579 00:32:36,154 --> 00:32:38,688 Sometimes, the crust gets ruptured. 580 00:32:38,690 --> 00:32:42,825 Anything that basically changes the geometry of the pulsar 581 00:32:42,827 --> 00:32:45,695 can change the rate at which it spins. 582 00:32:45,697 --> 00:32:47,230 So, what could be powerful enough 583 00:32:47,232 --> 00:32:50,633 to cause these starquakes? 584 00:32:50,635 --> 00:32:51,634 It's hard to believe 585 00:32:51,636 --> 00:32:54,037 that there's any force in the universe 586 00:32:54,039 --> 00:32:57,106 that could deform the matter inside of a neutron star, 587 00:32:57,108 --> 00:32:59,842 which is undergoing tremendous gravity. 588 00:32:59,844 --> 00:33:01,444 But when it comes to a neutron star, 589 00:33:01,446 --> 00:33:04,647 if there's one thing that can do it, it's magnetism. 590 00:33:04,649 --> 00:33:06,382 Extreme magnetic fields 591 00:33:06,384 --> 00:33:09,185 within the star can get so twisted 592 00:33:09,187 --> 00:33:11,921 they can rip the crust wide open. 593 00:33:11,923 --> 00:33:14,591 And so, the surface can restructure itself, 594 00:33:14,593 --> 00:33:16,125 and constantly reshape. 595 00:33:16,127 --> 00:33:18,794 And just a tiny reconfiguration 596 00:33:18,796 --> 00:33:20,564 of the surface of a neutron star, 597 00:33:20,566 --> 00:33:22,198 on the order of a few millimeters, 598 00:33:22,200 --> 00:33:26,736 would be associated with an enormous release of energy. 599 00:33:26,738 --> 00:33:28,805 The neutron star's immense gravity 600 00:33:28,807 --> 00:33:34,009 smooths over the star's surface almost instantaneously. 601 00:33:34,011 --> 00:33:36,480 It's like the glitch never happened. 602 00:33:40,017 --> 00:33:42,084 When it comes to neutron stars, 603 00:33:42,086 --> 00:33:46,756 there is no end to magnetic mayhem. 604 00:33:46,758 --> 00:33:48,691 Meet the reigning champion 605 00:33:48,693 --> 00:33:53,228 in the universal "strongest magnetic field" competition ... 606 00:33:53,230 --> 00:33:55,764 the magnetar. 607 00:33:55,766 --> 00:33:59,302 1 in 10 neutron stars formed during a supernova 608 00:33:59,304 --> 00:34:01,771 becomes a magnetar. 609 00:34:01,773 --> 00:34:06,376 The thing about magnetars, as is implied in their name ... 610 00:34:06,378 --> 00:34:08,578 the magnetic field on them is so strong, 611 00:34:08,580 --> 00:34:11,114 that even somebody who is used to using big numbers ... 612 00:34:11,116 --> 00:34:12,915 like, say, an astronomer ... 613 00:34:12,917 --> 00:34:15,985 is still kind of in awe of these things. 614 00:34:15,987 --> 00:34:18,321 Magnetars have a magnetic field 615 00:34:18,323 --> 00:34:22,525 one thousand trillion times stronger than that of earth's. 616 00:34:22,527 --> 00:34:24,460 This amount of magnetism 617 00:34:24,462 --> 00:34:29,332 will seriously mess up anything that comes close. 618 00:34:29,334 --> 00:34:31,800 Bullock: Any normal object that we are familiar with, 619 00:34:31,802 --> 00:34:35,471 if it got close to a magnetar, it would just be shredded. 620 00:34:35,473 --> 00:34:37,674 Any charged particle with any movement at all, 621 00:34:37,676 --> 00:34:39,609 would just be torn from its atom. 622 00:34:39,611 --> 00:34:42,945 It would be just an insane situation. 623 00:34:42,947 --> 00:34:47,350 Magnetars burn brightly, but their lives are brief. 624 00:34:47,352 --> 00:34:48,685 We think magnetars ... 625 00:34:48,687 --> 00:34:51,287 these intensely magnetized neutron stars ... 626 00:34:51,289 --> 00:34:53,156 can only be really short-lived. 627 00:34:53,158 --> 00:34:55,425 Their magnetic field is so powerful 628 00:34:55,427 --> 00:34:57,961 that it should decay over very rapid time scales, 629 00:34:57,963 --> 00:35:00,630 only on the order of a few ten thousand years. 630 00:35:00,632 --> 00:35:04,967 It seems their very strength leads to their downfall. 631 00:35:04,969 --> 00:35:06,970 That magnetic field is so strong 632 00:35:06,972 --> 00:35:09,972 that it's picking up material around it, and accelerating it. 633 00:35:09,974 --> 00:35:12,041 Well, that acts like a drag, slowing it down. 634 00:35:12,043 --> 00:35:15,177 So, over time, the spin of the neutron star slows, 635 00:35:15,179 --> 00:35:16,946 and the magnetic field dies away. 636 00:35:19,250 --> 00:35:20,583 During their lives, 637 00:35:20,585 --> 00:35:24,186 magnetars operate very differently than pulsars. 638 00:35:24,188 --> 00:35:25,854 They don't have beams. 639 00:35:25,856 --> 00:35:28,858 Their magnetic fields shoot out gigantic bursts 640 00:35:28,860 --> 00:35:32,261 of high-intensity radiation. 641 00:35:32,263 --> 00:35:35,932 But recently, astronomers have spotted one neutron star 642 00:35:35,934 --> 00:35:38,468 that's hard to classify. 643 00:35:38,470 --> 00:35:42,639 It behaves like a stellar Jekyll and Hyde. 644 00:35:44,743 --> 00:35:48,544 So, this particular neutron star is a really weird example. 645 00:35:48,546 --> 00:35:51,013 It behaves both like a radio pulsar, 646 00:35:51,015 --> 00:35:53,950 and also a highly-magnetized magnetar. 647 00:35:53,952 --> 00:35:56,219 It has the extreme magnetic fields, 648 00:35:56,221 --> 00:35:59,021 it can have these magnetic outbursts, 649 00:35:59,023 --> 00:36:01,691 but it also has this strong jet of radiation 650 00:36:01,693 --> 00:36:02,892 coming out of its poles. 651 00:36:02,894 --> 00:36:07,029 It's almost like it has a split personality. 652 00:36:07,031 --> 00:36:09,298 When first sighted in 2000, 653 00:36:09,300 --> 00:36:11,767 this star was emitting radio waves ... 654 00:36:11,769 --> 00:36:14,703 typical pulsar behavior. 655 00:36:14,705 --> 00:36:18,707 Then, 16 years later, it stopped pulsing, 656 00:36:18,709 --> 00:36:23,179 and suddenly started sending out massive X-ray bursts ... 657 00:36:23,181 --> 00:36:26,115 the actions of a magnetar. 658 00:36:26,117 --> 00:36:29,118 Scientists were baffled. 659 00:36:29,120 --> 00:36:32,321 We don't know if this thing is a pulsar turning into a magnetar, 660 00:36:32,323 --> 00:36:34,924 or a magnetar turning into a pulsar. 661 00:36:34,926 --> 00:36:37,860 One theory is that these X-ray bursts happened 662 00:36:37,862 --> 00:36:41,930 because the star's magnetic field suddenly twisted. 663 00:36:41,932 --> 00:36:46,402 The stress became so great, the star cracked wide open, 664 00:36:46,404 --> 00:36:50,406 releasing the x-rays from the fractured crust. 665 00:36:50,408 --> 00:36:52,675 A neutron star is the densest material 666 00:36:52,677 --> 00:36:54,543 that we know of in the universe. 667 00:36:54,545 --> 00:36:55,811 And yet, we've seen things 668 00:36:55,813 --> 00:36:58,281 that actually make it shift and pull apart. 669 00:36:58,283 --> 00:37:00,883 This neutron star is actually ripping itself apart 670 00:37:00,885 --> 00:37:02,885 under the forces of the magnetic field. 671 00:37:02,887 --> 00:37:04,420 If this is the case, 672 00:37:04,422 --> 00:37:08,891 placid neutron stars turn into raging magnetars, 673 00:37:08,893 --> 00:37:12,428 growing old disgracefully. 674 00:37:12,430 --> 00:37:14,364 When you think about the life cycle of a human being, 675 00:37:14,366 --> 00:37:16,299 we seem to kind of slow down over age, 676 00:37:16,301 --> 00:37:17,767 become a little more calmer. 677 00:37:17,769 --> 00:37:19,368 Neutron stars do the opposite. 678 00:37:19,370 --> 00:37:21,237 They can be spinning faster than they were 679 00:37:21,239 --> 00:37:22,504 when they were formed, 680 00:37:22,506 --> 00:37:24,774 and the magnetic field can get stronger over time. 681 00:37:24,776 --> 00:37:28,045 It's sort of a reverse aging process. 682 00:37:28,047 --> 00:37:31,248 But these strange changes are extremely rare. 683 00:37:31,250 --> 00:37:36,319 Most pulsars are as regular as clockwork. 684 00:37:36,321 --> 00:37:38,254 Pulsars are normally incredibly regular. 685 00:37:38,256 --> 00:37:41,524 You can literally set your watch to the timing of their pulse. 686 00:37:41,526 --> 00:37:43,993 And it's this stability that we may use 687 00:37:43,995 --> 00:37:47,797 in our future exploration of the universe. 688 00:37:47,799 --> 00:37:49,598 You know, if you're a starship Captain, 689 00:37:49,600 --> 00:37:52,735 what you need is a galactic GPS system. 690 00:37:52,737 --> 00:37:55,838 Well it turns out, neutron stars may be the answer. 691 00:38:11,189 --> 00:38:12,989 Astronomers often compare 692 00:38:12,991 --> 00:38:17,260 the steady flash of spinning neutron stars, called "pulsars," 693 00:38:17,262 --> 00:38:19,394 to cosmic lighthouses. 694 00:38:19,396 --> 00:38:23,132 These flashes are not only remarkably reliable, 695 00:38:23,134 --> 00:38:28,737 each pulsar has its very own distinct flickering beam. 696 00:38:28,739 --> 00:38:31,208 Each one has a slightly different frequency. 697 00:38:31,210 --> 00:38:33,943 Each one has a slightly different rate. 698 00:38:33,945 --> 00:38:37,346 Anyone in the galaxy, no matter where you are, 699 00:38:37,348 --> 00:38:43,553 can all agree on the positions of these pulsars. 700 00:38:43,555 --> 00:38:45,954 The unique signature of pulsars 701 00:38:45,956 --> 00:38:48,557 opens up intriguing possibilities 702 00:38:48,559 --> 00:38:50,160 for the future of space travel. 703 00:38:55,633 --> 00:38:58,033 straughn: We would basically be using pulsars 704 00:38:58,035 --> 00:39:01,036 to be able to sort of triangulate where we're at. 705 00:39:01,038 --> 00:39:03,239 And because those pulses are so precise, 706 00:39:03,241 --> 00:39:06,442 we can use that in a similar way that we use GPS satellites 707 00:39:06,444 --> 00:39:07,944 that are stationed above the earth. 708 00:39:10,982 --> 00:39:13,782 Using pulsars as navigational aids 709 00:39:13,784 --> 00:39:15,585 is not a new idea. 710 00:39:15,587 --> 00:39:18,988 It was recognized by the NASA voyager mission 711 00:39:18,990 --> 00:39:22,058 in the 1970's. 712 00:39:22,060 --> 00:39:24,393 Affixed to the surface of those spacecraft 713 00:39:24,395 --> 00:39:25,595 is a golden record. 714 00:39:25,597 --> 00:39:27,729 And on the plate that covers that record 715 00:39:27,731 --> 00:39:31,067 is a pulsar map, which in principle could tell 716 00:39:31,069 --> 00:39:34,536 an advanced alien civilization how to find earth, 717 00:39:34,538 --> 00:39:37,006 because it uses the position of earth 718 00:39:37,008 --> 00:39:39,207 relative to 14 known pulsars, 719 00:39:39,209 --> 00:39:41,410 as, effectively, a way to triangulate 720 00:39:41,412 --> 00:39:42,878 the position of our planet 721 00:39:42,880 --> 00:39:45,815 relative to all of these pulsars. 722 00:39:45,817 --> 00:39:51,820 Aliens haven't made contact, but NASA still uses pulsar maps. 723 00:39:51,822 --> 00:39:53,755 NASA recently launched a satellite 724 00:39:53,757 --> 00:39:55,424 called "nicer sextant" 725 00:39:55,426 --> 00:39:57,961 that exists on the international space station, 726 00:39:57,963 --> 00:40:00,763 that is being used to test these types of theories. 727 00:40:09,506 --> 00:40:11,908 they've used pulsars to figure out the location 728 00:40:11,910 --> 00:40:13,910 of an object orbiting around the earth 729 00:40:13,912 --> 00:40:16,246 at 17,000 miles an hour, 730 00:40:16,248 --> 00:40:18,047 and they were able to pinpoint its location 731 00:40:18,049 --> 00:40:19,581 to within three miles. 732 00:40:19,583 --> 00:40:21,717 That's pretty incredible. 733 00:40:21,719 --> 00:40:26,054 By recognizing their position relative to known pulsars, 734 00:40:26,056 --> 00:40:29,725 future space missions could navigate the universe. 735 00:40:36,333 --> 00:40:39,335 neutron stars are gonna take us on this incredible journey ... 736 00:40:39,337 --> 00:40:40,736 something as necessary 737 00:40:40,738 --> 00:40:42,604 as knowing where you are in the galaxy. 738 00:40:42,606 --> 00:40:44,540 We could be many hundreds of light years away, 739 00:40:44,542 --> 00:40:46,275 but neutron stars can actually show us 740 00:40:46,277 --> 00:40:47,810 where in the milky way we are. 741 00:40:55,686 --> 00:40:56,952 I read a lot of science fiction, 742 00:40:56,954 --> 00:40:59,688 and I love the idea of being able to go 743 00:40:59,690 --> 00:41:02,158 from star to star, planet to planet. 744 00:41:02,160 --> 00:41:05,828 It's kind of weird to think that, in the future, 745 00:41:05,830 --> 00:41:08,364 as a galactic coordinate grid, 746 00:41:08,366 --> 00:41:12,701 we might wind up using these gigantic atomic nuclei, 747 00:41:12,703 --> 00:41:15,739 these rapidly spinning, bizarrely-constructed, 748 00:41:15,741 --> 00:41:20,176 magnetic, fiercely gravitational objects like neutron stars. 749 00:41:23,381 --> 00:41:26,115 Neutron stars have come a long way 750 00:41:26,117 --> 00:41:30,853 since being mistaken for little green men. 751 00:41:30,855 --> 00:41:35,391 Once overlooked as astronomical oddities, 752 00:41:35,393 --> 00:41:42,866 they've now taken center stage as genuine stellar superstars. 753 00:41:42,868 --> 00:41:45,333 What's really exciting about neutron stars is that, 754 00:41:45,335 --> 00:41:47,670 we're at the beginning of studying them. 755 00:41:47,672 --> 00:41:49,938 We're not at the conclusion. We've learned a lot, 756 00:41:49,940 --> 00:41:51,741 but there's a lot more to be learned. 757 00:41:51,743 --> 00:41:56,412 Sutter: From the humble neutron comes the most powerful, 758 00:41:56,414 --> 00:41:59,949 the most rapid, the strongest magnetic field, 759 00:41:59,951 --> 00:42:03,619 the most exotic objects in the cosmos. 760 00:42:03,621 --> 00:42:05,421 I love the idea of a Phoenix, 761 00:42:05,423 --> 00:42:07,957 something actually rising from its own ashes. 762 00:42:07,959 --> 00:42:10,426 You think something dies, and that's the end of the story, 763 00:42:10,428 --> 00:42:12,094 but something even more beautiful, 764 00:42:12,096 --> 00:42:14,563 even more fascinating, comes afterwards. 765 00:42:14,565 --> 00:42:16,699 I told you at the beginning, and you didn't believe me, 766 00:42:16,701 --> 00:42:18,100 but now, I hope you do ... 767 00:42:18,102 --> 00:42:20,769 neutron stars are the most fascinating 768 00:42:20,771 --> 00:42:23,305 astrophysical objects in the universe. 61102

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